1. Field of the Invention
This invention relates to an apparatus for automatically mounting electronic components on a substrate, and more particularly to an automatic mounting apparatus for the mounting of chip-type circuit elements of the special-type such as IFT, DiPIC, a semifixed resistor or the like on a substrate for a printed circuit board.
2. Description of the Prior Art
Conventionally, the automatic fitted mounting of a chip-type circuit element of the special-type such as IFT, DiPIC (Dual-in-line Packaging Integrated Circuit Component), a semifixed resistor or the like (hereinafter referred to as "special-type chip" or "chip") on a substrate such as that for a printed circuit board has been typically carried out in a manner such that a magazine in which a plurality of chips arranged in a row are received is transferred to a position at which the chip is to be fittedly mounted on a substrate by means of an X-Y table and then a mounting head receives a chip fed from the magazine and mounts it on the substrate.
Although such a conventional procedure does not cause any important problem in the operation of sequentially mounting on a substrate only one kind of chips taken out from a single magazine, difficulties are encountered when various kinds of chips fed from a plurality of magazines respectively receiving therein chips which are different in kind from each other are to be mounted on a single substrate. This is because an X-Y table in such an apparatus for transferring each of the magazines to the mounting position must be highly complicated in construction, and it is substantially impossible to carry out the mounting operation with a high speed. In addition, such a chip feed mechanism is not suitable for rapid mounting because it is required to individually separate chips received in the magazine in order to individually and successively transfer the chips to the position of a mounting head, resulting in much time being necessary. Also, the feed mechanism fails to accomplish the constant individual and successive feeding of chips.
Further, a plurality of magazines each having a plurality of special-type chips received therein have been vertically arranged in a cartridge in order to ensure that the mounting operation is successively carried out for a long period of time. This exhibits another advantage of reducing needed space for installation. However, such arrangement requires that empty magazines are rapidly discharged from the cartridge when they are to be replaced with chip charged magazines. Also, in order to discharge the empty magazines without hindering the mounting operation, it is desired to employ a structure which allows the emtpy magazines to be prearranged in the cartridge prior to the discharge.
Also, a conventional automatic mounting apparatus is so constructed that the picking-up of a chip by a mounting head is carried out through a chuck or vacuum nozzle mounted on the lower end thereof and the mounting of the chip on a substrate is carried out by vertically moving the chuck or vacuum nozzle by means of an actuation cylinder of the mounting nozzle. However, a special-type chip unfortunately has a plurality of terminal pins mounted on the lower end thereof. Thus, the holding of the special-type chip by the conventional chuck or vacuum nozzle is not sufficient to mount the chip on a substrate because it is highly difficult to position the terminal pins with respect to the corresponding through-holes of the substrate, and the terminal pins hinder the smooth mounting. This requires a centering mechanism for accurately positioning the terminal pins with respect to the substrate.
Furthermore, the fitting of terminal pins of a special-type chip in a substrate during the chip mounting operation has been confirmed using a detecting device which is generally constructed in a manner such that positive and negative terminal pins of a chip are interposed between a pair of benders provided at the opposite upper ends of the device and voltage is applied across the chip between the benders, so that a success in application of the voltage indicates the fitting of terminal pins of the chip in the substrate and a failure in the application indicates the misfitting. However, the detecting mechanism of such construction requires the adjustment of applied voltage because the voltage to be applied must be determined depening upon the capacity of a chip.